view tests/test-narrow-expanddirstate.t @ 42377:0546ead39a7e stable

manifest: avoid corruption by dropping removed files with pure (issue5801)

Previously, removed files would simply be marked by overwriting the first byte
with NUL and dropping their entry in `self.position`.  But no effort was made to
ignore them when compacting the dictionary into text form.  This allowed them to
slip into the manifest revision, since the code seems to be trying to minimize
the string operations by copying as large a chunk as possible.  As part of this,
compact() walks the existing text based on entries in the `positions` list, and
consumed everything up to the next position entry.   This typically resulted in
a ValueError complaining about unsorted manifest entries.

Sometimes it seems that files do get dropped in large repos- it seems to
correspond to there being a new entry that would take the same slot.  A much
more trivial problem is that if the only changes were removals, `_compact()`
didn't even run because `__delitem__` doesn't add anything to `self.extradata`.
Now there's an explicit variable to flag this, both to allow `_compact()` to
run, and to avoid searching the manifest in cases where there are no removals.

In practice, this behavior was mostly obscured by the check in fastdelta() which
takes a different path that explicitly drops removed files if there are fewer
than 1000 changes.  However, timeless has a repo where after rebasing tens of
commits, a totally different path[1] is taken that bypasses the change count
check and hits this problem.

[1] https://www.mercurial-scm.org/repo/hg/file/2338bdea4474/mercurial/manifest.py#l1511

  $ . "$TESTDIR/narrow-library.sh"

  $ hg init master
  $ cd master

  $ mkdir inside
  $ echo inside > inside/f1
  $ mkdir outside
  $ echo outside > outside/f2
  $ mkdir patchdir
  $ echo patch_this > patchdir/f3
  $ hg ci -Aqm 'initial'

  $ cd ..

  $ hg clone --narrow ssh://user@dummy/master narrow --include inside
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets dff6a2a6d433
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd narrow

  $ mkdir outside
  $ echo other_contents > outside/f2
  $ hg tracked | grep outside
  [1]
  $ hg files | grep outside
  [1]
  $ hg status

`hg status` did not add outside.
  $ hg tracked | grep outside
  [1]
  $ hg files | grep outside
  [1]

Unfortunately this is not really a candidate for adding to narrowhg proper,
since it depends on some other source for providing the manifests (when using
treemanifests) and file contents. Something like a virtual filesystem and/or
remotefilelog. We want to be useful when not using those systems, so we do not
have this method available in narrowhg proper at the moment.
  $ cat > "$TESTTMP/expand_extension.py" <<EOF
  > import os
  > import sys
  > 
  > from mercurial import encoding
  > from mercurial import extensions
  > from mercurial import localrepo
  > from mercurial import match as matchmod
  > from mercurial import narrowspec
  > from mercurial import patch
  > from mercurial import util as hgutil
  > 
  > narrowspecexpanded = False
  > def expandnarrowspec(ui, repo, newincludes=None):
  >   if not newincludes:
  >     return
  >   if getattr(repo, '_narrowspecexpanded', False):
  >     return
  >   repo._narrowspecexpanded = True
  >   import sys
  >   newincludes = set([newincludes])
  >   includes, excludes = repo.narrowpats
  >   currentmatcher = narrowspec.match(repo.root, includes, excludes)
  >   includes = includes | newincludes
  >   if not repo.currenttransaction():
  >     ui.develwarn(b'expandnarrowspec called outside of transaction!')
  >   repo.setnarrowpats(includes, excludes)
  >   narrowspec.copytoworkingcopy(repo)
  >   newmatcher = narrowspec.match(repo.root, includes, excludes)
  >   added = matchmod.differencematcher(newmatcher, currentmatcher)
  >   for f in repo[b'.'].manifest().walk(added):
  >     repo.dirstate.normallookup(f)
  > 
  > def reposetup(ui, repo):
  >   class expandingrepo(repo.__class__):
  >     def narrowmatch(self, *args, **kwargs):
  >       with repo.wlock(), repo.lock(), repo.transaction(
  >           b'expandnarrowspec'):
  >         expandnarrowspec(ui, repo,
  >                          encoding.environ.get(b'DIRSTATEINCLUDES'))
  >       return super(expandingrepo, self).narrowmatch(*args, **kwargs)
  >   repo.__class__ = expandingrepo
  > 
  > def extsetup(unused_ui):
  >   def overridepatch(orig, ui, repo, *args, **kwargs):
  >     with repo.wlock():
  >       expandnarrowspec(ui, repo, encoding.environ.get(b'PATCHINCLUDES'))
  >       return orig(ui, repo, *args, **kwargs)
  > 
  >   extensions.wrapfunction(patch, b'patch', overridepatch)
  > EOF
  $ cat >> ".hg/hgrc" <<EOF
  > [extensions]
  > expand_extension = $TESTTMP/expand_extension.py
  > EOF

Since we do not have the ability to rely on a virtual filesystem or
remotefilelog in the test, we just fake it by copying the data from the 'master'
repo.
  $ cp -a ../master/.hg/store/data/* .hg/store/data
Do that for patchdir as well.
  $ cp -a ../master/patchdir .

`hg status` will now add outside, but not patchdir.
  $ DIRSTATEINCLUDES=path:outside hg status
  M outside/f2
  $ hg tracked | grep outside
  I path:outside
  $ hg files | grep outside > /dev/null
  $ hg tracked | grep patchdir
  [1]
  $ hg files | grep patchdir
  [1]

Get rid of the modification to outside/f2.
  $ hg update -C .
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

This patch will not apply cleanly at the moment, so `hg import` will break
  $ cat > "$TESTTMP/foo.patch" <<EOF
  > --- patchdir/f3
  > +++ patchdir/f3
  > @@ -1,1 +1,1 @@
  > -this should be "patch_this", but its not, so patch fails
  > +this text is irrelevant
  > EOF
  $ PATCHINCLUDES=path:patchdir hg import -p0 -e "$TESTTMP/foo.patch" -m ignored
  applying $TESTTMP/foo.patch
  patching file patchdir/f3
  Hunk #1 FAILED at 0
  1 out of 1 hunks FAILED -- saving rejects to file patchdir/f3.rej
  abort: patch failed to apply
  [255]
  $ hg tracked | grep patchdir
  [1]
  $ hg files | grep patchdir > /dev/null
  [1]

Let's make it apply cleanly and see that it *did* expand properly
  $ cat > "$TESTTMP/foo.patch" <<EOF
  > --- patchdir/f3
  > +++ patchdir/f3
  > @@ -1,1 +1,1 @@
  > -patch_this
  > +patched_this
  > EOF
  $ PATCHINCLUDES=path:patchdir hg import -p0 -e "$TESTTMP/foo.patch" -m message
  applying $TESTTMP/foo.patch
  $ cat patchdir/f3
  patched_this
  $ hg tracked | grep patchdir
  I path:patchdir
  $ hg files | grep patchdir > /dev/null